The difficulty of cooling high power electronic systems such as microprocessor systems has grown in recent years as a result of demand for vastly more powerful processors combined with a similarly strong demand for smaller system form factors. Thus, introduction of faster, higher performance semiconductors coincides with a concomitant increase in heat concentration problems. The generated thermal energy is intense with semiconductor chips that dissipate more than 100 watts of power.
Various structures and techniques may be used to attain suitable thermal engineering. Heat is generated by microelectronic chips and is removed to the surrounding air stream. Flowing heat is countered by thermal resistance impeding heat removal. Semiconductor and integrated circuit performance and reliability are absolutely constrained by temperature. Failure rate increases exponentially with rise in junction temperature with a myriad of device temperature-related failure modes including aspects of thermal runaway, gate dielectric strength, electro-migration diffusion, junction fatigue, electrical parameter shifts, and others, any of which may result in semiconductor failure.
Thermal engineering approaches typically involve supply of ventilation of ambient air around processing units including supply of simple ventilation holes or slots and installation of motorized fans in processing system cabinets. Other thermal engineering approaches include usage of fan-type assemblies mounted on or near heat-dissipating electronic components and devices. These techniques commonly realize only nominal benefit often with a disproportionate increase in system cost and complexity.